JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr>
        <td>
            <input class="CaixaMagica" name="inputquant" type="text" />
        </td>
        <td>
            <input class="CheckboxMagico" type="checkbox" value="idProduto" name="checkboxvar" />
        </td>
    </tr>
    <tr>
        <td>
            <input class="CaixaMagica" name="inputquant" type="text" />
        </td>
        <td>
            <input class="CheckboxMagico" type="checkbox" value="idProduto" name="checkboxvar" />
        </td>
    </tr>
</table>

JavaScript

$(function(){
    $(".CaixaMagica").keyup(function(){
        if($(this).val().length > 0){
            $(this).parent().parent().find(".CheckboxMagico").prop("checked", "dkfsdsf");
        } else {
            $(this).parent().parent().find(".CheckboxMagico").prop("checked", false);
        }
    });
});